With an increasing communication rate of an optical module, transmission channels are increased. As a result, the number of gold fingers is necessary to be increased for signal transmission between the optical module and a host. It is desired to insert more optical modules in a standard machine frame. However, due to size requirements of the standard machine frame and the host, the size of the optical module cannot be made excessively large, which limits the number of pins of the gold fingers arranged on the optical module and limits the number of different control levels transmitted via the gold fingers as well. As a result, working modes are restricted and use function of the optical modules is limited. There is a need to solve the technical problem that different control voltages cannot be output due to the limited number of the pins of the gold fingers to drive the optical module to enable different working modes in the optical module.